1. Technical Field
The present invention relates to a motor-incorporating reducer, which eliminates the risk of non-coaxial rotation of assembled components and thereby ensuring the drive's output torque and service life.
2. Description of Related Art
With the development of technology, mechanical automation has become a popular approach to saving labor costs and bringing great convenience to industry and human life. In general machinery, such as robots, robotic arms, machine tools and automated production systems, a driving assembly is typically used to provide rotational power. Such a driving assembly consists of a reducer and a motor. Therein, a harmonic gear reducer, as compared to transmission mechanism using normal gears, has the advantages of high kinematic accuracy, high transmission ratio, light weight, high compactness and high loading capacity, and is extensively used in automated machinery.
Two known applications of the combination between a harmonic gear reducer and a motor are discussed herein. The first conventional device has its rotatory transmission shaft coaxially passing through a hollow motor shaft and extending outward, and has an output shaft sensor located at a rear opening at the hollow motor shaft and on a rear end of the rotatory transmission shaft protruding rearward. Since the motor rotator and the rotating shaft are two separated produced parts, when they are assembled, the resultant tolerance can make the motor rotator and the rotating shaft have non-coaxial rotations. In addition, the sensors for sensing the input and output angles are both located at the rear end of the motor rotator, so that overall drive is hard to be downsized and becomes bulky.
The second conventional device has its rotating shaft passing through the interior of the reducer and coaxially assembled to a wave generator, and has a rotary encoder installed on the rotating shaft corresponding to the rotary position sensor. Since the wave generator and the rotating shaft are two separated produced parts, when they are assembled, the resultant tolerance can cause non-coaxial rotations. Moreover, the rotary encoder installed on the rotating shaft can only read the input rotational speed.